1. Field
Apparatuses and methods consistent with exemplary embodiments relate to an ultrasonic probe, a method of operating the same, and a mounting device.
2. Description of the Related Art
An ultrasonic diagnostic imaging apparatus is an apparatus that emits ultrasound from a surface of an object into a target region inside the object, receives a reflected ultrasonic echo signal, and noninvasively obtains an image of blood flow or a tomogram of soft tissue.
When compared to other diagnostic imaging apparatuses such as a radiographic imaging apparatus using X-rays, a computerized tomography (CT) scanner, a magnetic resonance imaging (MRI) apparatus, and a nuclear medicine diagnostic imaging apparatus, an ultrasonic diagnostic imaging apparatus is small, inexpensive, and may display a diagnostic image in real time. Also, because an ultrasonic diagnostic imaging apparatus has no risk of radiation exposure, the ultrasonic diagnostic imaging apparatus has high stability. Accordingly, an ultrasonic diagnostic imaging apparatus is widely used to monitor the heart, an abdominal organ, and a urinary tract or urogenital system as well as a fetus in a pregnant woman.
An ultrasonic diagnostic imaging apparatus includes an ultrasonic probe that transmits ultrasound to an object and receives an ultrasonic echo signal reflected from the object to obtain an image of an internal body structure of the object.
In general, a piezoelectric material that generates ultrasound by converting electrical energy into mechanical vibration energy is widely used as a material for a transducer that generates ultrasound in an ultrasonic probe.
A capacitive micromachined ultrasonic transducer (cMUT) that is a concept in the field of transducers has been developed.
A cMUT that is an ultrasonic transducer for transmitting/receiving ultrasound by using vibration of hundreds or thousands of micromachined membranes is manufactured based on micro-electro-mechanical system (MEMS) technology. A capacitor is formed by forming a lower electrode and an insulating layer on a semiconductor substrate that is used during a general semiconductor process, forming an air-gap on the insulating layer including the lower electrode, forming a membrane having a thickness that is several to thousands of Å on the air-gap, and forming an upper electrode on the membrane.
When alternating current (AC) is applied to the capacitor, the membrane begins to vibrate and thus ultrasound is generated. In contrast, when the membrane is forced to vibrate due to external ultrasound, the capacitance of the capacitor changes. Ultrasound is received by detecting the change in capacitance.
Because one cMUT has a diameter that is just tens of μm, an array of tens of thousands of cMUTs has a size that is just several mm. Also, because tens of thousands of sensors may be simultaneously accurately arranged at desired positions by using one semiconductor manufacturing process and cMUT elements are connected to application specific integrated circuits (ASICs) by using chip bonding such as flip-chip bonding to apply an electrical signal to a cMUT, process complexity due to wiring may be overcome.
Due to such advantages, a cMUT is suitably used to manufacture a 2D array of transducers that is a trend, and helps to develop a multi-channel transducer.
The amount of heat that is generated by an electrical circuit for driving a probe including a relatively small number of channels of transducers is just about 1 W, which is small enough to be naturally released through a case of the probe. However, the amount of heat that is generated when multi-channel transducers are included is as much as about 7 W. Accordingly, there is a demand for a technology for dissipating heat from an ultrasonic probe and cooling the ultrasonic probe.